Problem with proxies parameter in AsyncClient after update to 0.28.0

[diazdiego1]

After updating to version 0.28.1, the proxies parameter is no longer accepted in httpx.AsyncClient, resulting in the following error:

TypeError("AsyncClient.init() got an unexpected keyword argument 'proxies'")

Before this update, the proxies parameter was correctly used to configure proxies directly in the AsyncClient instance. However, with the current version, attempting to pass the proxies parameter to configure proxies results in the error mentioned above.

Steps to Reproduce:

1. Install version 0.27.2 of httpx in your virtual environment.
2. Try to use AsyncClient with the proxies parameter configured:

import httpx

proxy_config = {
    'http://': 'http://your.proxy.here',
    'https://': 'https://your.proxy.here'
}

async with httpx.AsyncClient(proxies=proxy_config) as client:
    response = await client.get('https://www.example.com')

How can I configure multiple proxies (both HTTP and HTTPS) in version 0.28.1 of httpx, considering that the proxies parameter is no longer accepted?